Method for making photovoltaic devices using oxygenated semiconductor thin film layers

Abstract

A method for making a photovoltaic device is presented. The method includes steps of disposing a window layer on a substrate and disposing an absorber layer on the window layer. Disposing the window layer, the absorber layer, or both layers includes introducing a source material into a deposition zone, wherein the source material comprises oxygen and a constituent of the window layer, of the absorber layer or of both layers. The method further includes step of depositing a film that comprises the constituent and oxygen.

The invention claimed is: 
     
       1. A method for making a photovoltaic device, comprising:
 disposing a window layer over a substrate; 
 disposing an absorber layer over the window layer; 
 wherein disposing the window layer, disposing the absorber layer, or disposing the window layer and the absorber layer, comprises: 
 oxidizing a source material precursor to form a source material; then 
 introducing the source material into a deposition zone, and 
 thereafter, depositing a film comprising a constituent of the source material and oxygen. 
 
     
     
       2. A method for making a photovoltaic device, comprising:
 disposing a window layer over a substrate; 
 disposing an absorber layer over the window layer; wherein disposing the absorber layer, comprises: 
 oxidizing a source material precursor that comprises cadmium and tellurium to form a source material comprising a mixture of cadmium, tellurium and oxygen as at least one of an alloy and a compound; then 
 introducing the source material into a deposition zone; and 
 thereafter, depositing a film comprising cadmium telluride and oxygen. 
 
     
     
       3. A method for making a photovoltaic device, comprising:
 disposing a window layer over a substrate; 
 disposing an absorber layer over the window layer;
 wherein disposing the window layer, disposing the absorber layer, or disposing the window layer and disposing the absorber layer, comprises:
 introducing a source material into a deposition zone, wherein the source material comprises oxygen and a constituent element as a mixture of elements in at least one of an alloy and a compound of oxygen and the constituent element; the constituent element being a constituent of the window layer, of the absorber layer, or of the window layer and the absorber layer; and 
 depositing a film comprising the constituent element and oxygen. 
 
 
 
     
     
       4. The method of  claim 3 , wherein the window layer, the absorber layer, or the window layer and the absorber layer comprise a telluride, a selenide, a sulfide or a hydride. 
     
     
       5. The method of  claim 4 , wherein the window layer comprises a semiconductor material selected from the group consisting of cadmium sulfide, cadmium selenide, zinc telluride, zinc selenide, zinc sulfide, indium selenide, indium sulfide, and zinc hydride. 
     
     
       6. The method of  claim 4 , wherein the absorber layer comprises a semiconductor material selected from the group consisting of cadmium telluride, cadmium zinc telluride, cadmium sulfur telluride, cadmium manganese telluride, and cadmium magnesium telluride. 
     
     
       7. The method of the  claim 3 , wherein disposing the window layer comprises depositing via a vacuum deposition technique selected from the group consisting of evaporation deposition, electron beam physical vapor deposition, sputter deposition, cathode arc deposition, and pulsed laser deposition. 
     
     
       8. The method of  claim 3 , wherein disposing the absorber layer comprises depositing via a deposition technique selected from the group consisting of closed space sublimation, diffused transport deposition, and vapor transport deposition. 
     
     
       9. The method of  claim 3 , further comprising oxidizing a source material precursor to form the source material. 
     
     
       10. The method of  claim 9 , wherein the steps disposing a window layer over a substrate and disposing an absorber layer over the window layer are performed within a deposition chamber; and wherein the step of oxidizing a source material precursor is performed outside the deposition chamber. 
     
     
       11. The method of  claim 9 , wherein oxidizing the source material precursor comprises oxidizing at an oxygen pressure ranging from about 100 mTorr to about 10 Torr. 
     
     
       12. The method of  claim 11 , wherein oxidizing the source material precursor comprises oxidizing at an oxygen pressure ranging from about 400 mTorr to about 1 Torr. 
     
     
       13. The method of  claim 9 , wherein oxidizing the source material precursor comprises oxidizing at a temperature ranging from about 550 degrees Celsius to about 750 degrees Celsius. 
     
     
       14. The method of  claim 3 , wherein depositing the film comprises depositing the film to a thickness ranging from about 50 nanometers to about 4 micrometers. 
     
     
       15. The method of  claim 3 , wherein depositing the film comprises depositing the film with a concentration of oxygen that ranges from about 4×10 17  cm −3  to 2×10 19  cm −3  within the film. 
     
     
       16. The method of  claim 15 , wherein depositing the film comprises depositing the film having a uniform distribution of the concentration of oxygen throughout the film. 
     
     
       17. The method of  claim 15 , wherein depositing the film comprises depositing the film having a graded profile of the concentration of oxygen through a thickness of the film. 
     
     
       18. The method of  claim 3 , wherein the source material comprises an oxide of the constituent element. 
     
     
       19. The method of  claim 3 , further comprising a step of introducing an additional source material into the deposition zone prior to the step of depositing a film; wherein the additional source material comprises an additional constituent of the window layer, of the absorber layer, or of both layers, such that the step of depositing a film includes depositing a film comprising the constituent element, the additional constituent and oxygen. 
     
     
       20. The method of  claim 3 , further comprising a step of subjecting the film comprising the constituent element and oxygen to a process treatment. 
     
     
       21. The method of  claim 20 , wherein the process treatment is selected from one of: a sulfurization process, a treatment with cadmium chloride, an acid etching process, and combination of a treatment with cadmium chloride and an acid etching process.